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[virtio] Add legacy driver for KVM virtio-net

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This patch adds support for the virtio-net adapter provided by KVM.

Written by Laurent Vivier <Laurent.Vivier@bull.net> for Etherboot.
Wrapped as legacy driver for gPXE by Stefan Hajnoczi
<stefanha@gmail.com>.
This commit is contained in:
Stefan Hajnoczi 2008-08-01 16:55:49 +01:00
parent 481a21798d
commit 50babca5da
4 changed files with 723 additions and 0 deletions
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492
src/drivers/net/virtio-net.c Normal file
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/* virtio-net.c - etherboot driver for virtio network interface
*
* (c) Copyright 2008 Bull S.A.S.
*
* Author: Laurent Vivier <Laurent.Vivier@bull.net>
*
* some parts from Linux Virtio PCI driver
*
* Copyright IBM Corp. 2007
* Authors: Anthony Liguori <aliguori@us.ibm.com>
*
* some parts from Linux Virtio Ring
*
* Copyright Rusty Russell IBM Corporation 2007
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*
*/
#include "etherboot.h"
#include "nic.h"
#include "virtio-ring.h"
#include "virtio-pci.h"
#include "virtio-net.h"
#define BUG() do { \
printf("BUG: failure at %s:%d/%s()!\n", \
__FILE__, __LINE__, __FUNCTION__); \
while(1); \
} while (0)
#define BUG_ON(condition) do { if (condition) BUG(); } while (0)
/* Ethernet header */
struct eth_hdr {
unsigned char dst_addr[ETH_ALEN];
unsigned char src_addr[ETH_ALEN];
unsigned short type;
};
struct eth_frame {
struct eth_hdr hdr;
unsigned char data[ETH_FRAME_LEN];
};
typedef unsigned char virtio_queue_t[PAGE_MASK + vring_size(MAX_QUEUE_NUM)];
/* TX: virtio header and eth buffer */
static struct virtio_net_hdr tx_virtio_hdr;
static struct eth_frame tx_eth_frame;
/* RX: virtio headers and buffers */
#define RX_BUF_NB 6
static struct virtio_net_hdr rx_hdr[RX_BUF_NB];
static unsigned char rx_buffer[RX_BUF_NB][ETH_FRAME_LEN];
/* virtio queues and vrings */
enum {
RX_INDEX = 0,
TX_INDEX,
QUEUE_NB
};
static virtio_queue_t queue[QUEUE_NB];
static struct vring vring[QUEUE_NB];
static u16 free_head[QUEUE_NB];
static u16 last_used_idx[QUEUE_NB];
static u16 vdata[QUEUE_NB][MAX_QUEUE_NUM];
/*
* Virtio PCI interface
*
*/
static int vp_find_vq(struct nic *nic, int queue_index)
{
struct vring * vr = &vring[queue_index];
u16 num;
/* select the queue */
outw(queue_index, nic->ioaddr + VIRTIO_PCI_QUEUE_SEL);
/* check if the queue is available */
num = inw(nic->ioaddr + VIRTIO_PCI_QUEUE_NUM);
if (!num) {
printf("ERROR: queue size is 0\n");
return -1;
}
if (num > MAX_QUEUE_NUM) {
printf("ERROR: queue size %d > %d\n", num, MAX_QUEUE_NUM);
return -1;
}
/* check if the queue is already active */
if (inl(nic->ioaddr + VIRTIO_PCI_QUEUE_PFN)) {
printf("ERROR: queue already active\n");
return -1;
}
/* initialize the queue */
vring_init(vr, num, (unsigned char*)&queue[queue_index]);
/* activate the queue
*
* NOTE: vr->desc is initialized by vring_init()
*/
outl((unsigned long)virt_to_phys(vr->desc) >> PAGE_SHIFT,
nic->ioaddr + VIRTIO_PCI_QUEUE_PFN);
return num;
}
/*
* Virtual ring management
*
*/
static void vring_enable_cb(int queue_index)
{
vring[queue_index].avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
}
static void vring_disable_cb(int queue_index)
{
vring[queue_index].avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
}
/*
* vring_free
*
* put at the begin of the free list the current desc[head]
*/
static void vring_detach(int queue_index, unsigned int head)
{
struct vring *vr = &vring[queue_index];
unsigned int i;
/* find end of given descriptor */
i = head;
while (vr->desc[i].flags & VRING_DESC_F_NEXT)
i = vr->desc[i].next;
/* link it with free list and point to it */
vr->desc[i].next = free_head[queue_index];
wmb();
free_head[queue_index] = head;
}
/*
* vring_more_used
*
* is there some used buffers ?
*
*/
static inline int vring_more_used(int queue_index)
{
wmb();
return last_used_idx[queue_index] != vring[queue_index].used->idx;
}
/*
* vring_get_buf
*
* get a buffer from the used list
*
*/
static int vring_get_buf(int queue_index, unsigned int *len)
{
struct vring *vr = &vring[queue_index];
struct vring_used_elem *elem;
u32 id;
int ret;
elem = &vr->used->ring[last_used_idx[queue_index] % vr->num];
wmb();
id = elem->id;
if (len != NULL)
*len = elem->len;
ret = vdata[queue_index][id];
vring_detach(queue_index, id);
last_used_idx[queue_index]++;
return ret;
}
static void vring_add_buf(int queue_index, int index, int num_added)
{
struct vring *vr = &vring[queue_index];
int i, avail, head;
BUG_ON(queue_index >= QUEUE_NB);
head = free_head[queue_index];
i = head;
if (queue_index == TX_INDEX) {
BUG_ON(index != 0);
/* add header into vring */
vr->desc[i].flags = VRING_DESC_F_NEXT;
vr->desc[i].addr = (u64)virt_to_phys(&tx_virtio_hdr);
vr->desc[i].len = sizeof(struct virtio_net_hdr);
i = vr->desc[i].next;
/* add frame buffer into vring */
vr->desc[i].flags = 0;
vr->desc[i].addr = (u64)virt_to_phys(&tx_eth_frame);
vr->desc[i].len = ETH_FRAME_LEN;
i = vr->desc[i].next;
} else if (queue_index == RX_INDEX) {
BUG_ON(index >= RX_BUF_NB);
/* add header into vring */
vr->desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
vr->desc[i].addr = (u64)virt_to_phys(&rx_hdr[index]);
vr->desc[i].len = sizeof(struct virtio_net_hdr);
i = vr->desc[i].next;
/* add frame buffer into vring */
vr->desc[i].flags = VRING_DESC_F_WRITE;
vr->desc[i].addr = (u64)virt_to_phys(&rx_buffer[index]);
vr->desc[i].len = ETH_FRAME_LEN;
i = vr->desc[i].next;
}
free_head[queue_index] = i;
vdata[queue_index][head] = index;
avail = (vr->avail->idx + num_added) % vr->num;
vr->avail->ring[avail] = head;
wmb();
}
static void vring_kick(struct nic *nic, int queue_index, int num_added)
{
struct vring *vr = &vring[queue_index];
wmb();
vr->avail->idx += num_added;
mb();
if (!(vr->used->flags & VRING_USED_F_NO_NOTIFY))
vp_notify(nic, queue_index);
}
/*
* virtnet_disable
*
* Turn off ethernet interface
*
*/
static void virtnet_disable(struct nic *nic)
{
int i;
for (i = 0; i < QUEUE_NB; i++) {
vring_disable_cb(i);
vp_del_vq(nic, i);
}
vp_reset(nic);
}
/*
* virtnet_poll
*
* Wait for a frame
*
* return true if there is a packet ready to read
*
* nic->packet should contain data on return
* nic->packetlen should contain length of data
*
*/
static int virtnet_poll(struct nic *nic, int retrieve)
{
unsigned int len;
u16 token;
struct virtio_net_hdr *hdr;
if (!vring_more_used(RX_INDEX))
return 0;
if (!retrieve)
return 1;
token = vring_get_buf(RX_INDEX, &len);
BUG_ON(len > sizeof(struct virtio_net_hdr) + ETH_FRAME_LEN);
hdr = &rx_hdr[token]; /* FIXME: check flags */
len -= sizeof(struct virtio_net_hdr);
nic->packetlen = len;
memcpy(nic->packet, (char *)rx_buffer[token], nic->packetlen);
/* add buffer to desc */
vring_add_buf(RX_INDEX, token, 0);
vring_kick(nic, RX_INDEX, 1);
return 1;
}
/*
*
* virtnet_transmit
*
* Transmit a frame
*
*/
static void virtnet_transmit(struct nic *nic, const char *destaddr,
unsigned int type, unsigned int len, const char *data)
{
/*
* from http://www.etherboot.org/wiki/dev/devmanual :
* "You do not need more than one transmit buffer."
*/
/* FIXME: initialize header according to vp_get_features() */
tx_virtio_hdr.flags = 0;
tx_virtio_hdr.csum_offset = 0;
tx_virtio_hdr.csum_start = 0;
tx_virtio_hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE;
tx_virtio_hdr.gso_size = 0;
tx_virtio_hdr.hdr_len = 0;
/* add ethernet frame into vring */
BUG_ON(len > sizeof(tx_eth_frame.data));
memcpy(tx_eth_frame.hdr.dst_addr, destaddr, ETH_ALEN);
memcpy(tx_eth_frame.hdr.src_addr, nic->node_addr, ETH_ALEN);
tx_eth_frame.hdr.type = htons(type);
memcpy(tx_eth_frame.data, data, len);
vring_add_buf(TX_INDEX, 0, 0);
/*
* http://www.etherboot.org/wiki/dev/devmanual
*
* "You should ensure the packet is fully transmitted
* before returning from this routine"
*/
while (vring_more_used(TX_INDEX)) {
mb();
udelay(10);
}
vring_kick(nic, TX_INDEX, 1);
/* free desc */
(void)vring_get_buf(TX_INDEX, NULL);
}
static void virtnet_irq(struct nic *nic __unused, irq_action_t action)
{
switch ( action ) {
case DISABLE :
vring_disable_cb(RX_INDEX);
vring_disable_cb(TX_INDEX);
break;
case ENABLE :
vring_enable_cb(RX_INDEX);
vring_enable_cb(TX_INDEX);
break;
case FORCE :
break;
}
}
static void provide_buffers(struct nic *nic)
{
int i;
for (i = 0; i < RX_BUF_NB; i++)
vring_add_buf(RX_INDEX, i, i);
/* nofify */
vring_kick(nic, RX_INDEX, i);
}
static struct nic_operations virtnet_operations = {
.connect = dummy_connect,
.poll = virtnet_poll,
.transmit = virtnet_transmit,
.irq = virtnet_irq,
};
/*
* virtnet_probe
*
* Look for a virtio network adapter
*
*/
static int virtnet_probe(struct nic *nic, struct pci_device *pci)
{
u32 features;
int i;
/* Mask the bit that says "this is an io addr" */
nic->ioaddr = pci->ioaddr & ~3;
/* Copy IRQ from PCI information */
nic->irqno = pci->irq;
printf("I/O address 0x%08x, IRQ #%d\n", nic->ioaddr, nic->irqno);
adjust_pci_device(pci);
vp_reset(nic);
features = vp_get_features(nic);
if (features & (1 << VIRTIO_NET_F_MAC)) {
vp_get(nic, offsetof(struct virtio_net_config, mac),
nic->node_addr, ETH_ALEN);
printf("MAC address ");
for (i = 0; i < ETH_ALEN; i++) {
printf("%02x%c", nic->node_addr[i],
(i == ETH_ALEN - 1) ? '\n' : ':');
}
}
/* initialize emit/receive queue */
for (i = 0; i < QUEUE_NB; i++) {
free_head[i] = 0;
last_used_idx[i] = 0;
memset((char*)&queue[i], 0, sizeof(queue[i]));
if (vp_find_vq(nic, i) == -1)
printf("Cannot register queue #%d\n", i);
}
/* provide some receive buffers */
provide_buffers(nic);
/* define NIC interface */
nic->nic_op = &virtnet_operations;
/* driver is ready */
vp_set_features(nic, features & (1 << VIRTIO_NET_F_MAC));
vp_set_status(nic, VIRTIO_CONFIG_S_DRIVER | VIRTIO_CONFIG_S_DRIVER_OK);
return 1;
}
static struct pci_device_id virtnet_nics[] = {
PCI_ROM(0x1af4, 0x1000, "virtio-net", "Virtio Network Interface"),
};
PCI_DRIVER ( virtnet_driver, virtnet_nics, PCI_NO_CLASS );
DRIVER ( "VIRTIO-NET", nic_driver, pci_driver, virtnet_driver,
virtnet_probe, virtnet_disable );

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src/drivers/net/virtio-net.h Normal file
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#ifndef _VIRTIO_NET_H_
# define _VIRTIO_NET_H_
/* The feature bitmap for virtio net */
#define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */
#define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */
#define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */
#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
#define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */
#define VIRTIO_NET_F_GUEST_TSO6 8 /* Guest can handle TSOv6 in. */
#define VIRTIO_NET_F_GUEST_ECN 9 /* Guest can handle TSO[6] w/ ECN in. */
#define VIRTIO_NET_F_GUEST_UFO 10 /* Guest can handle UFO in. */
#define VIRTIO_NET_F_HOST_TSO4 11 /* Host can handle TSOv4 in. */
#define VIRTIO_NET_F_HOST_TSO6 12 /* Host can handle TSOv6 in. */
#define VIRTIO_NET_F_HOST_ECN 13 /* Host can handle TSO[6] w/ ECN in. */
#define VIRTIO_NET_F_HOST_UFO 14 /* Host can handle UFO in. */
struct virtio_net_config
{
/* The config defining mac address (if VIRTIO_NET_F_MAC) */
u8 mac[6];
} __attribute__((packed));
/* This is the first element of the scatter-gather list. If you don't
* specify GSO or CSUM features, you can simply ignore the header. */
struct virtio_net_hdr
{
#define VIRTIO_NET_HDR_F_NEEDS_CSUM 1 // Use csum_start, csum_offset
uint8_t flags;
#define VIRTIO_NET_HDR_GSO_NONE 0 // Not a GSO frame
#define VIRTIO_NET_HDR_GSO_TCPV4 1 // GSO frame, IPv4 TCP (TSO)
/* FIXME: Do we need this? If they said they can handle ECN, do they care? */
#define VIRTIO_NET_HDR_GSO_TCPV4_ECN 2 // GSO frame, IPv4 TCP w/ ECN
#define VIRTIO_NET_HDR_GSO_UDP 3 // GSO frame, IPv4 UDP (UFO)
#define VIRTIO_NET_HDR_GSO_TCPV6 4 // GSO frame, IPv6 TCP
#define VIRTIO_NET_HDR_GSO_ECN 0x80 // TCP has ECN set
uint8_t gso_type;
uint16_t hdr_len;
uint16_t gso_size;
uint16_t csum_start;
uint16_t csum_offset;
};
#endif /* _VIRTIO_NET_H_ */

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#ifndef _VIRTIO_PCI_H_
# define _VIRTIO_PCI_H_
/* A 32-bit r/o bitmask of the features supported by the host */
#define VIRTIO_PCI_HOST_FEATURES 0
/* A 32-bit r/w bitmask of features activated by the guest */
#define VIRTIO_PCI_GUEST_FEATURES 4
/* A 32-bit r/w PFN for the currently selected queue */
#define VIRTIO_PCI_QUEUE_PFN 8
/* A 16-bit r/o queue size for the currently selected queue */
#define VIRTIO_PCI_QUEUE_NUM 12
/* A 16-bit r/w queue selector */
#define VIRTIO_PCI_QUEUE_SEL 14
/* A 16-bit r/w queue notifier */
#define VIRTIO_PCI_QUEUE_NOTIFY 16
/* An 8-bit device status register. */
#define VIRTIO_PCI_STATUS 18
/* An 8-bit r/o interrupt status register. Reading the value will return the
* current contents of the ISR and will also clear it. This is effectively
* a read-and-acknowledge. */
#define VIRTIO_PCI_ISR 19
/* The bit of the ISR which indicates a device configuration change. */
#define VIRTIO_PCI_ISR_CONFIG 0x2
/* The remaining space is defined by each driver as the per-driver
* configuration space */
#define VIRTIO_PCI_CONFIG 20
/* Virtio ABI version, this must match exactly */
#define VIRTIO_PCI_ABI_VERSION 0
static inline u32 vp_get_features(struct nic *nic)
{
return inl(nic->ioaddr + VIRTIO_PCI_HOST_FEATURES);
}
static inline void vp_set_features(struct nic *nic, u32 features)
{
outl(features, nic->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
}
static inline void vp_get(struct nic *nic, unsigned offset,
void *buf, unsigned len)
{
u8 *ptr = buf;
unsigned i;
for (i = 0; i < len; i++)
ptr[i] = inb(nic->ioaddr + VIRTIO_PCI_CONFIG + offset + i);
}
static inline u8 vp_get_status(struct nic *nic)
{
return inb(nic->ioaddr + VIRTIO_PCI_STATUS);
}
static inline void vp_set_status(struct nic *nic, u8 status)
{
if (status == 0) /* reset */
return;
outb(status, nic->ioaddr + VIRTIO_PCI_STATUS);
}
static inline void vp_reset(struct nic *nic)
{
outb(0, nic->ioaddr + VIRTIO_PCI_STATUS);
(void)inb(nic->ioaddr + VIRTIO_PCI_ISR);
}
static inline void vp_notify(struct nic *nic, int queue_index)
{
outw(queue_index, nic->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY);
}
static inline void vp_del_vq(struct nic *nic, int queue_index)
{
/* select the queue */
outw(queue_index, nic->ioaddr + VIRTIO_PCI_QUEUE_SEL);
/* deactivate the queue */
outl(0, nic->ioaddr + VIRTIO_PCI_QUEUE_PFN);
}
#endif /* _VIRTIO_PCI_H_ */

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#ifndef _VIRTIO_RING_H_
# define _VIRTIO_RING_H_
#define PAGE_SHIFT (12)
#define PAGE_SIZE (1<<PAGE_SHIFT)
#define PAGE_MASK (PAGE_SIZE-1)
/* Status byte for guest to report progress, and synchronize features. */
/* We have seen device and processed generic fields (VIRTIO_CONFIG_F_VIRTIO) */
#define VIRTIO_CONFIG_S_ACKNOWLEDGE 1
/* We have found a driver for the device. */
#define VIRTIO_CONFIG_S_DRIVER 2
/* Driver has used its parts of the config, and is happy */
#define VIRTIO_CONFIG_S_DRIVER_OK 4
/* We've given up on this device. */
#define VIRTIO_CONFIG_S_FAILED 0x80
#define MAX_QUEUE_NUM (512)
#define VRING_DESC_F_NEXT 1
#define VRING_DESC_F_WRITE 2
#define VRING_AVAIL_F_NO_INTERRUPT 1
#define VRING_USED_F_NO_NOTIFY 1
struct vring_desc
{
u64 addr;
u32 len;
u16 flags;
u16 next;
};
struct vring_avail
{
u16 flags;
u16 idx;
u16 ring[0];
};
struct vring_used_elem
{
u32 id;
u32 len;
};
struct vring_used
{
u16 flags;
u16 idx;
struct vring_used_elem ring[];
};
struct vring {
unsigned int num;
struct vring_desc *desc;
struct vring_avail *avail;
struct vring_used *used;
};
static inline void vring_init(struct vring *vr,
unsigned int num, unsigned char *queue)
{
unsigned int i;
unsigned long pa;
vr->num = num;
/* physical address of desc must be page aligned */
pa = virt_to_phys(queue);
pa = (pa + PAGE_MASK) & ~PAGE_MASK;
vr->desc = phys_to_virt(pa);
vr->avail = (struct vring_avail *)&vr->desc[num];
/* physical address of used must be page aligned */
pa = virt_to_phys(&vr->avail->ring[num]);
pa = (pa + PAGE_MASK) & ~PAGE_MASK;
vr->used = phys_to_virt(pa);
for (i = 0; i < num - 1; i++)
vr->desc[i].next = i + 1;
vr->desc[i].next = 0;
}
#define vring_size(num) \
(((((sizeof(struct vring_desc) * num) + \
(sizeof(struct vring_avail) + sizeof(u16) * num)) \
+ PAGE_MASK) & ~PAGE_MASK) + \
(sizeof(struct vring_used) + sizeof(struct vring_used_elem) * num))
#endif /* _VIRTIO_RING_H_ */